The present invention relates to intumescent seals, and in particular to intumescent seals for doors, door frames or the like which are used to prevent dispersion of smoke, fumes and the like across the perimeter of the door or door frame during a fire.
Fire resistant seals using intumescent material have been previously proposed using intumescent materials which are well-known and which, when subjected to elevated temperature, undergo a substantial expansion to produce a foam of fire resistant material, often referred to as a "puff".
Previously proposed intumescent seals have been developed to seal the air space between doors and frames in the event of a fire. These seals are intended to prevent penetration by hot gases, smoke, heat and flames for several hours. Such previously proposed seals are disclosed, for example, in U.S. Pat. Nos. 4,045,930; 3,566,541; 4,660,338; 4,144,688; 4,246,304; 3,955,330; 4,733,514; and 4,649,089. These devices are relatively simple seals, which are secured in place in the door frame or the like. They are difficult to accurately align and, because of variability in expansion, will not form a perfect seal under all circumstances.
It is an object of the present invention to provide an improved intumescent seal.
Another object of the present invention is to provide an intumescent seal which is safe and efficient in operation.
Yet another object of the present invention is to provide an adjustable spring loaded intumescent seal.
A further object of the present invention is to provide an intumescent seal which is relatively simple in construction and which will assure proper sealing along the entire length of the seal.
In accordance with an aspect of the present invention a safe, efficient intumescent seal is provided which will prevent penetration across the seal of hot gases, smoke, heat and flames. The seal is preferably formed of a pair of the opposed first and second seal members, or seal means. Each seal member is adapted to be mounted within a channel or groove formed in the edge of a door and in the door frame. Each has an elongated generally channel-shaped housing member adapted to be mounted in a fixed position in the door or frame. The channel of the housing opens outwardly to face the opposed door or door frame. It contains a second housing or channel member that is adjustably mounted therein. The mounting is accomplished by a plurality of screws securing the second housing in the channel of the first housing. A leaf spring is mounted in the space between the housings to bias the second housing away from the first housing. Therefore, the second housing "floats" in the first housing.
In one of the seal means, the second housing is filled with an intumescent material. The second housing of the other seal member contains a flexible neoprene or rubber seal strip which is adapted to engage the intumescent material of its facing seal member when the door is shut, in normal operation, to provide an initial barrier to the penetration of smoke and gases, until the intumescent material expands.
The seal means of the invention are mounted in the frame of the door and the door itself. They may also be used in the opposed edges of a double door arrangement.
The assignee of the present application, Zero International Inc., manufactures and supplies the intumescent material used in accordance with the present invention. This material is provided as either a "soft puff" or "hard puff" material. Soft puff intumescent material will start to foam and expand at approximately 250.degree. F. which will continue to expand with increase in heat. This product is offered by Zero under Nos. FS3003 and FS6886. A "hard puff" intumescent material expands all at once, once a particular temperature, say 450.degree. F., is reached.